• Resources Recycling
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• v.29 no.1
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• pp.43-52
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• 2020

The objectives of this study were to identify the optimal mix of foam concrete with the low-strength and high-flow for the repairing ground subsidence situation emergently by utilizing a large amount of industrial by-products and evaluate the possibility by applying it to the site. The factors of the experiment were the mixing ratio of mixing water and a foaming agent and the mixing ratio of foam over paste volume. The optimal mix identified by the experiment was applied to the field and basic properties were evaluated. The results of the experiment showed that the optimal mixing ratio of mixing water and the foaming agent was 10%. Moreover, when the mixing ratio of pre-foam over paste volume was 170%, it satisfied the target. However, to ensure stable quality when applying to the field, the foam mixing ratio was set 140% for the field application. The field application test of foam concrete with the low-strength and high-flow using an eco-friendly binder satisfied all target performances. Therefore, the possibility of using it as a mixture and construction method for a ground repair system is confirmed. However, there was a quality deviation between the upper part and the lower part due to the separation between foam and paste. Consequently, further studies are needed to improve it.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.11
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• pp.66-76
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• 2009

The motion estimation in video encoding system occupies the biggest part. So, we require the motion estimator with efficient structure for real-time operation. And for motion estimator's implementation, it is desired to design hardware module of an exclusive use that perform the encoding process at high speed. This paper proposes motion estimation detection block(MED), 41 SADs(Sum of Absolute Difference) calculation block, minimum SAD calculation and motion vector generation block based on parallel processing. The parallel processing can reduce effectively the amount of the operation. The minimum SAD calculation and MED block uses the pre-computation technique for reducing switching activity of the input signal. It results in high-speed operation. The MED and 41 SADs calculation blocks are composed of adder tree which causes the problem of critical path. So, the structure of adder tree has changed the most commonly used ripple carry adder(RCA) with carry skip adder(CSA). It enables adder tree to operate at high speed. In addition, as we enabled to easily control key variables such as control signal of search range from the outside, the efficiency of hardware structure increased. Simulation and FPGA verification results show that the delay of MED block generating the critical path at the motion estimator is reduced about 19.89% than the conventional strukcture.

• Korean Journal of Social Welfare Studies
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• v.48 no.1
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• pp.5-21
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• 2017

The purpose of this study was to examine the effects of the employment policy for persons with disabilities on their employment rates. The subjects were 10 OECD counties of which policies are based on quotas or the prohibition of discrimination. The time-series data for the analysis were collected for 12 years from 2000 to 2011. A Panel-Corrected Standard Error(PCSE) analysis was conducted for the time-series cross-sectional data of this study. As a result, unemployment rates, proportions of persons with disabilities, and public expenditures on disability and sickness benefits(in % GDP) were statistically significant among control variables, while the coverages of discrimination prohibition and the types of delivery systems of vocational rehabilitation for persons with disabilities among the employment policy variables. The wider the coverages of discrimination prohibition are, the higher the employment rates of the disabled are. In addition, the employment rates of the disabled are higher in countries with specialized delivery systems for vocational rehabilitation than in countries with general delivery systems for vocational rehabilitation.

• Korean Journal of Social Welfare Studies
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• v.44 no.3
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• pp.57-83
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• 2013

There has neither been enough research on how to approach the concept of active aging through an integrated view nor an examination to verify the relationship between preparation for old age and active aging in later life. Therefore, this research aims to verify that the elderly, who have prepared for their later life, affected their active aged life. In addition, by setting up self-efficacy and social support as mediator in the research model, this paper looks into the psycho-social resource mechanism of the relationship in depth. In order to verify the correlation of two variables, the Seoul welfare panel data, a mediating model structured by psycho-social resources created by Seoul welfare foundation in 2010, was used. The total sample size was a group of 1,492 elders aged over 65. When it came to our research methods, structured equation analysis was applied to verify the mediating effect and theoretical background. The results revealed that physical preparation, financial preparation, social preparation and leisure preparation directly affected their active aging level positively, thus, psycho-social resources showed a partial mediating effect between preparation for old age of the past and active aging level. The research implications are as follows. First, this research makes an effort to approach the concept of preparation for old age with an integrated perspective through making a construct by entire preparation types. Second, it will attempt to verify the relationship between preparation for old age in the past and active aging in terms of multi-dimension is meaningful. Third, this research reveals the function of psycho-social resource, self-efficacy and social support within the relationship. As far as the partial mediating effect is concerned, preparation for old age education for the middle-aged class should be modified as a decent field to enhance of the elderly.

• Korean Journal of Social Welfare Studies
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• v.45 no.3
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• pp.237-262
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• 2014

Little is known about the relationships among adolescents'academic stress, self-efficacy, and internalization externalization. Much less is known about whether there is gender differences in the relationships. This study aims to examine (1) the effects of academic stress on internalization externalization, (2) whether self-efficacy mediates the relationships between academic stress and internalization externalization, and (3) whether there is gender difference in the relationships. For these purposes, we used Structural Equation Modeling and multi group analysis involving 2,844 middle school students participated in the Korean Youth Panel Survey. The results are as follows. First, adolescent's academic stress affected internalization externalization. Second, self-efficacy mediated the relationship between academic stress and internalization externalization. Finally, the multiple group analysis results indicated that the path coefficient between academic stress and internalization of girls was significantly greater than that of boys. Based on these results, we discussed theoretical and practical implications and suggested directions for future research on academic stress coping processes among adolescents.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.729-737
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• 2019

Fatty pancreas is an abnormal process of lipid deposition in cells, resulting in increased fat tissue and obesity. The result is a risk factor for cardiovascular and metabolic diseases. The aim of this study was to evaluate the usefulness of pancreatic fat as a predictor of cardiovascular disease and metabolic syndrome in pancreatic ultrasonography. In 407 patients who underwent a comprehensive screening at the W Health Care Center in Busan from September 2. 2018 to December 31, 2018, the degree of fat deposition in the pancreas was evaluated as the degree of mild, moderate. Data on non-obstructive atherosclerosis, BMI, hyperlipidemia, hypertension, and diabetes were collected to assess the association of pancreatic fat deposition with cardiovascular disease and metabolic syndrome. In addition, we tried to analyze the correlation between liver dysfunction and thyroid dysfunction as the degree of fat pancreas increased. We examined the relationship between six parameters including atherosclerosis, BMI, hyperlipidemia, hypertension, diabetes, liver dysfunction, and thyroid dysfunction among patients with fatty pancreas. We concluded that the carotid intima-media thickness of atherosclerosis, which is a risk factor of cardiovascular disease, is most closely related to fatty pancreas.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.113-125
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• 2011

In this study, recent trends of the annual precipitation, the annual maximum precipitation of different durations and the rain days over several thresholds(i.e. 0, 10, 20, 40, 60 and 80 mm/day) according to the different local features were analyzed using daily precipitation data of 59 weather stations between 1973 and 2009. To analyze the variability according to the regional characteristics, 59 weather stations were classified by elevations, latitudes, longitudes, river basins, inland or shore(east sea, south sea, west sea) area and the level of urbanization. Results demonstrated that overall trend of variables increases except rain day. Results according to the regional characteristics showed that the increase trend becomes stronger with elevation increase. The increase trend of Han river basin is largest and that of Youngsan river basin is smallest. Also the increase trend becomes stronger with latitude increase and that of East coast is larger than that of South coast since it may be caused by the regional difference of elevation. The increase trend of urban area is larger than that of rural area. Overall trend showed that increase trend becomes stronger with elevation and latitude increase.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.629-636
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• 2022

Domestic eco-friendly vehicles currently account for 5.8% of the total registered vehicles in Korea. Hydrogen vehicles, one of the representative eco-friendly vehicles, have grown rapidly as they have been expanded to the market based on the government's policy to boost the hydrogen industry. Therefore, it is time to expand the safety review of hydrogen vehicles in various directions according to the increase in supply. In this study, the effect of internal heat damage was analyzed when a jet flame was generated by a hydrogen car in a road tunnel. It was simulated using Fluent, and the amount of jet flame injection was selected in consideration of the hydrogen tank capacity of commercial hydrogen vehicles for road tunnels. In addition, the study was conducted with the direction of the jet flame and the nozzle distance from the tunnel wall as variables. From the results, when the jet flame erupted in the road tunnel, high radiant heat emission of more than 20 kW/m² was generated in most areas within ±5 m in the longitudinal direction based on the vehicle (spray nozzle) and 5 to 7 m in the lateral direction based on the adjacent tunnel wall.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.846-855
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• 2021

Eco-friendly and renewable energy sources are actively being researched in recent times, and of shore wind power generation requires advanced design technologies in terms of increasing the capacities of wind turbines and enlarging wind turbine installation vessels (WTIVs). The WTIV ensures that the hull is situated at a height that is not affected by waves. The most important part of the WTIV is the leg structure, which must respond dynamically according to the wave, current, and wind loads. In particular, the wave load is composed of irregular waves, and it is important to know the exact dynamic response. The dynamic response analysis uses a single degree of freedom (SDOF) method, which is a simplified approach, but it is limited owing to the consideration of random waves. Therefore, in industrial practice, the time-domain analysis of random waves is based on the multi degree of freedom (MDOF) method. Although the MDOF method provides high-precision results, its data convergence is sensitive and difficult to apply owing to design complexity. Therefore, a dynamic amplification factor (DAF) estimation formula is developed in this study to express the dynamic response characteristics of random waves through time-domain analysis based on different variables. It is confirmed that the calculation time can be shortened and accuracy enhanced compared to existing MDOF methods. The developed formula will be used in the initial design of WTIVs and similar structures.

• Korean Journal of Construction Engineering and Management
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• v.22 no.6
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• pp.34-43
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• 2021

While universities are making every effort to improve the housing welfare of university students by establishing new dormitories, the construction of school dormitories has intensified the conflict with other certified real estate businesses on the basis of their right to survival. Thus, it is necessary to analyze the causality in the conflict to coherently understand the conflict between these stakeholders. To do so, this study conducted a survey questionnaire on certified real estate businesses in the vicinity of private universities with dormitories in the metropolitan area. This study targeted licensed real estate brokerage agencies that conclude rental contracts in view of different stances, and control the real estate rental market by controling their conflict. Investigated the influence relationship between universities and licensed real estate brokerage agencies in relation to construction of private university dormitories and the effect of this conflict on management performance of licensed real estate brokerage agencies, and analyzed the relationship among relevant variables to see if their dormitory recognitions have a moderating effect. In addition to analyzing the causality of conflict level (perceived conflict, expressed conflict), conflict management, conflict outcome, and management performance, the study also verified the moderating effect of perception on dormitory and the mediating effect of conflict management. The results showed that conflict level had a negative (-) effect on conflict management, while the perceived conflict and conflict management of the conflict level had a negative (-) effect on the conflict outcome. In the relationship between perceived conflict and conflict outcome, conflict management had a complete mediating effect while expressed conflict had a partial mediating effect. Lastly, the perception of university dormitories did not have a moderating effect for the influence of conflict management on conflict outcome.